3.13 Producing monoclonal antibodies
How monoclonal antibodies are made: a mouse lymphocyte that makes the right antibody is fused with a tumour (myeloma) cell to make a hybridoma cell, which is cloned to produce large amounts of one identical antibody.
What monoclonal antibodies are
Key terms
- Monoclonal antibodies: identical antibodies produced from a single clone of cells. They are specific to one binding site on one antigen.
- Lymphocyte: a white blood cell that makes antibodies. It cannot divide in the laboratory.
- Myeloma cell: a type of tumour (cancer) cell that divides again and again.
- Hybridoma cell: a cell made by fusing a lymphocyte with a myeloma cell. It divides fast and makes one antibody.
Every antibody has a specific shape that binds to only one antigen. If we could make large amounts of a single antibody, we could use it to find or target one particular substance, such as a hormone, a pathogen or a cancer cell. The problem is that lymphocytes that make antibodies do not divide in the laboratory. Tumour cells do divide rapidly, but do not make antibodies. Combining the two solves the problem.
How they are made
- A mouse is injected with the chosen antigen.
- The mouse's lymphocytes start making antibodies against it. They are collected from the mouse, usually from its spleen.
- The lymphocytes are fused with tumour (myeloma) cells.
- This makes hybridoma cells. A hybridoma can both divide rapidly (from the tumour cell) and make the antibody (from the lymphocyte).
- A single hybridoma cell that makes the right antibody is chosen and cloned: it divides to make many identical cells.
- All the cells make the same antibody. Large amounts are collected and purified.
Because every antibody comes from one clone of cells, they are all identical: monoclonal.
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